Gamma scintigraphy: an evolving technology in pharmaceutical formulation development—Part 2

Digenis, George A.; Sandefer, Erik P.; Page, Richard C.; Döll, W

doi:10.1016/s1461-5347(98)00041-8

Cited by 12 publications

(14 citation statements)

References 14 publications

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“…These results strongly indicate that the transit rate or the residence time in the site of absorption is an important factor determining the extent of absorption in each site in-vivo. 42) To evaluate the GI transit rate for each segment in-vivo, a non-invasive technique, gamma scintigraphy, [43][44][45][46][47][48][49][50] was employed using unabsorbable compound, Tc-labeled diethylenetriamine-pentaacetic acid (DTPA) 42) with a gamma camera system (PRISM 3000-Odyssay, Picker International Inc., Cleveland, OH, U.S.A.). Using gamma scintigraphic technique, it is possible to simultaneously evaluate the GI transit and absorption of orally administered drug in the same individual.…”

Section: Absorption Behavior Of Orally Adminis-tered Drugs In Gi Tranmentioning

confidence: 99%

Gastrointestinal Transit and Drug Absorption

Kimura

Higaki

2002

Biological & Pharmaceutical Bulletin

170

114

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Oral drug administration is the most convenient and common for drug therapy and it is, therefore, very important and useful to estimate the absorbability of drugs and to predict the plasma concentration profile of drugs after oral administration for the development of novel drugs and/or novel dosage form and the designation of the dosage regimen. Generally, the absorbability of drugs has been estimated by in-situ recirculation studies, in-situ closed loop studies or the analysis by the simple compartment model. The information which can be obtained from these approaches is usually an absorption rate constant, ka. The ka value is generally the averaged one throughout the intestinal tract. However, there is the site-difference in drug absorbability [1][2][3][4] and variable residence time of drugs in each segment must make the contribution of each segment to drug absorption changed, resulting in the different absorbability as a whole. As for the drug absorption after oral administration, the gastrointestinal (GI) transit of a drug is also an important factor to determine the drug absorption and is so variable, as was influenced by not only individual differences, 5) but also the dosage conditions like meals, 6) disease states 7) and so on. Therefore, the absorbability and the residence time in each segment are the major determining factors for drug absorption after oral administration and very important for the analysis of drug absorption kinetics and the estimation of, and the prediction of plasma concentration profiles of drugs. However, the analysis and the estimation of drug absorption after oral administration have been usually performed by a simple compartment model, where even a process of gastric emptying is not included often. This kind of simple model cannot describe the irregular shape in the plasma concentration, which is often observed. Therefore, several models were proposed to analyze the plasma profile, [8][9][10][11] but they are not necessarily based on the practical phenomena, i.e. GI transit and site-different drug absorbability.We have developed a GI-Transit-Absorption (GITA) Model containing the GI transit and absorption processes to analyze and predict the plasma concentration profile after oral administration of aqueous drug solution.12) Although several efficient methods to estimate the absorption of orally administered drug by analyzing the GI disposition following oral administration (GI disposition analysis) have been reported, some are only focused on the gastric emptying based on a model having a stomach and an intestine compartment. 13,14) The other one estimated the intestinal transit of a drug using polyethylene glycol 4000 as a nonabsorbable marker, 10) but the actual data of intestinal transit were not utilized enough to analyze and predict the drug absorption kinetics. Although the analytical procedures for plasma profile of a drug absorbed from successive absorption sites along the GI tract have been also reported, [16][17][18] they just showed the concept and/or simulation stu...

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Section: Absorption Behavior Of Orally Adminis-tered Drugs In Gi Tranmentioning

confidence: 99%

Gastrointestinal Transit and Drug Absorption

Kimura

Higaki

2002

Biological & Pharmaceutical Bulletin

170

114

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“…The double-peak phenomenon is a typical example indicating the complex kinetics of drug absorption after oral dosing. Double peaks in plasma concentration-time profiles have been often observed after oral administration for many drugs (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18). Possible reasons for the double-peak phenomenon have also been proposed as follows: (a) the interaction between drugs and bile salts in the intestinal lumen (10,11), (b) the enterohepatic circulation (12,19), (c) the two different sites of drug absorption (13)(14)(15)(16)20), (d) the irregular pattern of gastric emptying (3)(4)(5)(6)(7)(8)(9).…”

Section: Introductionmentioning

confidence: 99%

Appearance of Double Peaks in Plasma Concentration–time Profile after Oral Administration Depends on Gastric Emptying Profile and Weight Function

et al. 2007

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“…Until now, pharmacoscintigraphy had been an important approach for providing information about GI transit of radiolabelled dosage forms dealing with drug release and subsequent drug absorption (3)(4)(5)(6)(7).…”

Section: Pharmacomagnetographymentioning

confidence: 99%

“…For many years, gamma scintigraphy was the standard method for the noninvasive monitoring of solid dosage forms in human GI tract (3)(4)(5). Scintigraphic studies are conducted after incorporating a radioactive marker into the formulation or by the use of neutron activation, i.e., a nonradioactive isotope is added and is converted to a radioactive isotope by exposure to a neutron flux (4,6).…”

Section: Introductionmentioning

confidence: 99%

“…Scintigraphic studies are conducted after incorporating a radioactive marker into the formulation or by the use of neutron activation, i.e., a nonradioactive isotope is added and is converted to a radioactive isotope by exposure to a neutron flux (4,6). The modality known as pharmacoscintigraphy, which combines scintigraphic outcome with pharmacokinetic assessment, has been applied to provide information about the transit of a variety of solid dosage forms and subsequent drug release and absorption (3)(4)(5)(6)(7).…”

Section: Introductionmentioning

confidence: 99%

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Biomagnetic Methods: Technologies Applied to Pharmaceutical Research

et al. 2010

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Biomagnetic methods have been designed for a wide range of applications. Recently, such methods have been proposed as alternatives to scintigraphy for evaluating of a number of pharmaceutical processes in vitro as well as under the influence of gastrointestinal physiological parameters. In this review, physical characterization as well as the most recent applications of Superconducting Quantum Interference Device (SQUID), Anisotropic Magnetoresistive (AMR) and AC Biosusceptometry (ACB) in the pharmaceutical research will be explored. Moreover, their current status and how these technologies can be employed to improve the knowledge about the impact of gastrointestinal physiology on drug delivery in association with pharmacokinetic outcomes, termed pharmacomagnetography, will be presented.

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Gamma scintigraphy: an evolving technology in pharmaceutical formulation development—Part 2

Cited by 12 publications

References 14 publications

Gastrointestinal Transit and Drug Absorption

Gastrointestinal Transit and Drug Absorption

Appearance of Double Peaks in Plasma Concentration–time Profile after Oral Administration Depends on Gastric Emptying Profile and Weight Function

Biomagnetic Methods: Technologies Applied to Pharmaceutical Research

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